Counting contact terms in B→VγB\to V\gamma decays

We clarify the origin and cancellation of contact terms in the weak annihilation amplitudes contributing to $B\to V \gamma$. It is demonstrated that the photon emission from the final-state quarks vanishes in the chiral limit of massless quarks. The contact terms in the QCD light-cone sum rule evaluation of the weak annihilation amplitudes are also discussed.Comment: 16 pages, 2 figures, Latex, ws-p8-50x6-00.cls, to be published in Sergei Matinian Festschrift ``From Integrable Models to Gauge Theories.'', Eds. V. Gurzadyan, A. Sedrakyan, World Scientific, 200

Axinos in Cosmology and at Colliders

The axino, the fermionic superpartner of the axion, is a well-motivated candidate for cold dark matter if it is the lightest supersymmetric particle. Since the axino couples very weakly to the matter multiplets, the next-to-lightest supersymmetric particle (NLSP) has a long lifetime, which has important consequences for both cosmology and collider phenomenology. Assuming that a charged slepton is the NLSP, we calculate the complete leading one- and two-loop contributions to its decay. We analyze in detail constraints on the parameters space from cosmology and discuss how this scenario can be probed at colliders. Scenarios in which both the axino and the gravitino are lighter than the long-lived charged slepton are also explored with particular emphasis on cosmological constraints and collider phenomenology.Comment: 64 pages, 22 figure

K−→π−aK^-\to\pi^- a at Next-to-Leading Order in Chiral Perturbation Theory

The weak decay $K^-\to\pi^- a$ is a powerful probe of axion-like particles (ALPs). In this work, we provide a comprehensive analysis of this process within chiral perturbation theory, extending existing calculations by including complete next-to-leading order (NLO) contributions and isospin-breaking corrections at first order in $(m_u-m_d)$. We show that the consistent incorporation of ALPs in the QCD and weak chiral Lagrangians requires a non-trivial extension of the corresponding operator bases, which we describe in detail. Furthermore, we show that in the presence of an ALP the so-called weak mass term, which is unobservable in the Standard Model, is non-redundant already at leading order. We find that NLO corrections associated with flavor-violating ALP couplings modify the leading-order result by a few percent, with only small uncertainties. On the contrary, the NLO corrections proportional to flavor-conserving ALP couplings lead to an $\mathcal{O}(20\%)$ reduction relative to the leading-order predictions. These corrections are accompanied by a large uncertainties mainly originating from the QCD low-energy constant $L_{4,r}$ as well as from the presence of various unknown weak low-energy constants. We emphasize the importance of a precise determination of these coupling parameters for the successful study of new physics in light meson decays.Comment: 35 pages, 8 figure

Health-related quality of life after radical prostatectomy and low-dose-rate brachytherapy for localized prostate cancer

To evaluate quality of life (QOL) after radical retropubic prostatectomy (RP) and low-dose-rate brachytherapy (BT)

Float, explode or sink: postmortem fate of lung-breathing marine vertebrates

What happens after the death of a marine tetrapod in seawater? Palaeontologists and neontologists have claimed that large lung-breathing marine tetrapods such as ichthyosaurs had a lower density than seawater, implying that their carcasses floated at the surface after death and sank subsequently after leakage of putrefaction gases (or ‘‘carcass explosions''). Such explosions would thus account for the skeletal disarticulation observed frequently in the fossil record. We examined the taphonomy and sedimentary environment of numerous ichthyosaur skeletons and compared them to living marine tetrapods, principally cetaceans, and measured abdominal pressures in human carcasses. Our data and a review of the literature demonstrate that carcasses sink and do not explode (and spread skeletal elements). We argue that the normally slightly negatively buoyant carcasses of ichthyosaurs would have sunk to the sea floor and risen to the surface only when they remained in shallow water above a certain temperature and at a low scavenging rate. Once surfaced, prolonged floating may have occurred and a carcass have decomposed gradually. Our conclusions are of significance to the understanding of the inclusion of carcasses of lung-breathing vertebrates in marine nutrient recycling. The postmortem fate has essential implications for the interpretation of vertebrate fossil preservation (the existence of complete, disarticulated fossil skeletons is not explained by previous hypotheses), palaeobathymetry, the physiology of modern marine lung-breathing tetrapods and their conservation, and the recovery of human bodies from seawate

Phenomenology of Mirror Fermions in the Littlest Higgs Model with T-Parity

Little Higgs models are an interesting alternative to explain electroweak symmetry breaking without fine-tuning. Supplemented with a discrete symmetry (T-parity) constraints from electroweak precision data are naturally evaded and also a viable dark matter candidate is obtained. T-parity implies the existence of new (mirror) fermions in addition to the heavy gauge bosons of the little Higgs models. In this paper we consider the effects of the mirror fermions on the phenomenology of the littlest Higgs model with T-parity at the LHC. We study the most promising production channels and decay chains for the new particles. We find that the mirror fermions have a large impact on the magnitude of signal rates and on the new physics signatures. Realistic background estimates are given.Comment: 13 p

Unstable particles in One Loop Calculations

We present a gauge invariant way to compute one loop corrections to processes involving the production and decay of unstable particles.Comment: 21 pages latex, <A HREF=http://pss058.psi.ch/preprints/unstablefull.ps>ps file, PSI-PR-93-22, REVISED. (Completely rewritten due to many complaints about the unclear exposition.